1922, American English, perhaps from high(way) + jacker "one who holds up." Originally "to rob (a bootlegger, smuggler, etc.) in transit;" sense of "seizing an aircraft in flight" is 1968 (also in 1961 variant skyjack), extended 1970s to any form of public transportation. Related: Hijacked; hijacking.

hijack

To commandeer a public vehicle, esp an airliner, for some extortionary or political purpose: Two more planes were hijacked to Cuba last week(1960s+)

To appropriate unjustifiably; annex; steal: The 40th anniversary of D-day was hijacked by Reagan's PR men/ When Petersen, the director, is stuck, he just hijacks an idea or two from Hitchcock to get him to the next point in the picture/ How was the Bharatiya Janata Party able to hijack Hinduism?(1980s+)

[origin uncertain; said to be fr the command High, Jack, telling a robbery victim to raise his hands; an early 1900s hobo sense, ''traveling hold-up man,'' is attested, which suggests that the source may be railroad and hobo slang; said to have originated in the California wheat fields and among the Wobblies; the name of the 1875 skit High Jack the Heeler is interesting but probably coincidental]

The Dictionary of American Slang, Fourth Edition by Barbara Ann Kipfer, PhD. and Robert L. Chapman, Ph.D.Copyright (C) 2007 by HarperCollins Publishers.Cite This Source